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Question on ADAU1452's internal LDO unit

Question asked by IRON on Nov 1, 2016
Latest reply on Nov 3, 2016 by DaveThib

Hello all,

I have 2 questions.

 

Question1

On the datasheet p.18, VDRIVE description says that the "STD2805" PNP pass transistor is recommended.

Also, on the datasheet p.32, "Voltage Regulator" section says as below.

 

"Ensure that the current gain of the transistor (β) is 200 or greater and the transistor is able to dissipate at least 1 W in the worst case."

 

 

Is it no problem to use another transistor if it satisfies the line above???

 

Question 2

Could you please tell me detailed information of how exactly the internal LDO works?

And how the external components work and why does the transistor needed?

For the hardware develop reason, the solid functional description is required.

Is it a switching regulator?

If so, could you tell me the switching frequency please.

Seems that the data sheet only has simplified description just as below.

 

Best Regards,

Yuta M

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